electronic subtraction
81Group (mathematics) — This article covers basic notions. For advanced topics, see Group theory. The possible manipulations of this Rubik s Cube form a group. In mathematics, a group is an algebraic structure consisting of a set together with an operation that combines …
82Pressure measurement — The construction of a bourdon tube gauge, construction elements are made of brass Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure pressure are called pressure gauges or vacuum gauges. A… …
83One-time pad — Excerpt from a one time pad In cryptography, the one time pad (OTP) is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit …
84PDP-8 — A PDP 8 on display at the Smithsonian s National Museum of American History in Washington, D.C.. This example is from the first generation of PDP 8s, built with discrete transistors and later known as the Straight 8. The 12 bit PDP 8 was the… …
85Celestial navigation — Celestial navigation, also known as astronavigation, is a position fixing technique that was devised to help sailors cross the featureless oceans without having to rely on dead reckoning to enable them to strike land. Celestial navigation uses… …
86Countdown (game show) — Countdown Title card since 2009. Genre Game show Created by Armand Jammot …
87CORDIC — Trigonometry History Usage Functions Generalized Inverse functions Further reading …
88E6B — pilots will still carry and use these Flight Computers. These flight computers are used during flight planning (on the ground before takeoff) to aid in calculating fuel burn, wind correction, time en route, and other items. In the air, the flight …
89Renaissance Learning — Type Public Traded as NASDAQ: RLRN Industry …
90Problem of Apollonius — In Euclidean plane geometry, Apollonius problem is to construct circles that are tangent to three given circles in a plane (Figure 1); two circles are tangent if they touch at a single point. Apollonius of Perga (ca. 262 BC ndash; ca. 190 BC)… …
